As was described by a disk manufacturer in the N.Y. Times, Jul. 1, 2002, “The plastic tray they sell you to carry your drive home is a higher gross margin product ” than the modern computer hard disk. Yet we demand that the disk include as much technology in today's world as a complex computer chip. This invention is directed to improving manufacture of such disks to permit the creation of higher technology on the disks and to help bring cost down.
U.S. Pat. Nos. 5,215,420 and 5,425,611 describe equipment that is primarily used to manufacture disks today. This equipment is available from Intevac, Inc. of Santa Clara, Calif. and is marketed as the MPD 250. The equipment includes a main chamber, entrance and output load locks, substrate load and unload stages and a plurality of processing stations. Disks are fed into the system transported and treated in processing stations and then are fed from the system as disks ready for use as hard disks in computer applications. Prior to the development of the MPD 250, there existed equipment in this field as described in U.S. Pat. No. 4,981,408 which equipment was at one time available from Varian Associates of Palo Alto, Calif. Another manufacturer in this field is Anelva Corporation of Fuchu, Japan. Anelva manufactures a unit designated the C-3040. One of its objectives is to deposit films of greater thickness on the substrate. Patents describing this system are U.S. Pat. Nos. 6,027,618, 6,228,439 B1 and 6,251,232 B1. These background patents are all incorporated into this disclosure by reference.
One fault with these prior art systems is that they occupy a rather large footprint. Some are excessively long. Others cover a generally rectangular area and this generally is an entire room. Since these units for the manufacture of disks are typically operated in clean rooms oversized units compel excessively sized and extremely expensive clean rooms.
Recently it has also become recognized that as the art has progressed it has become necessary to supplement the original systems with add-ons. For example, one such add-on is a lube station to lubricate disks before they are removed from the tool. This is described in U.S. Pat. No. 6,183,831 B1 and in the parent application Ser. No. 09/562,039, filed May 1, 2000. Another has to do with the deposition of carbon to create diamond like coatings using plasma enhanced CVD. This is described for example in U.S. Pat. Nos. 6,101,972, 6,203,862 and 6,368,678 B1.
In radial systems there is a limit as to how many processing stations can function as part of the unit. Typically, existing systems are limited to about 12 stations. Adding additional stations requires considerable redesign of the equipment and the factory facilities with the expectation that a system with more stations would increase its footprint considerably. In these systems the same substrate holder is generally used to carry the substrate to and through the various stations of the unit. If it becomes necessary or desirable to change the substrate holder this would require stopping operation of the system and its production of output. Also it has not been possible to do processing in these systems while the substrate is moving and this prevents the deposition of very thin layers which can be deposited when deposition is carried out in a pass by mode.
A linear machine has the same type of problems experienced with a radial system. It has a large footprint and to change the substrate holder, requires that the system and production be stopped. Any add-on, if possible, extends the footprint and eventually the number of stations would be controlled by space constraints of the facility.